The Yebatan Hydropower Station in southwest China started filling its reservoir on Monday, reaching the final phase before its first power-generating units go online.

As a key project in the nation's 14th Five-Year Plan (2021-2025), this marks the official start of the final stage for the first batch of generating units at the concrete double-curvature arch dam hydropower station under construction at the highest altitude in China.

The Yebatan Hydropower Station, a vital part of the upper Jinsha River clean-energy hub, is being built on the main channel of the Jinsha River at the border of Baiyu County, Sichuan Province, and Konjo County, Xizang Autonomous Region in southwest China.

The station has a total installed capacity of 2,240 MW, with a maximum dam height of 217 meters. During construction, Chinese engineers extracted a record-breaking 38.1-meter-long concrete core sample in May.

Reservoir filling will occur in two stages. The first stage, commencing today, will elevate the water level to the 2,855-meter minimum operating level, enabling the first generating units to start operating by the end of this year," said Du Xiaofan, head of the engineering management department, Yebatan branch, Huadian Jinsha River Upstream Hydropower Development Co.

The second stage is the initial operation period, expected to last until October next year, when the water level will be raised to the 2,889-meter normal pool level. This will maximize the coordinated dispatch and operation capability of the cascade power stations on the upper Jinsha River,

As a vital part of China's west-to-east power transfer project, once it is fully operational, the Yebatan Station will produce over 10.2 billion kWh of electricity annually, equivalent to saving nearly 4 million tonnes of standard coal and reducing carbon dioxide emissions by about 7.37 million tonnes each year.

The clean electricity produced will be transmitted to central China through the world's highest-altitude large-capacity hydropower-photovoltaic hybrid DC transmission line, the Jinshang-Hubei ±800 kV UHV DC project. This is important for improving China's energy mix and supporting local economic and social growth.

Construction of the hydropower station's main structure began in September 2018, and full operation is scheduled for 2026.